Cement compositions may be used in a variety of subterranean operations, such as, in the production and exploration of hydrocarbons, e.g., oil, gas, and other hydrocarbons, onshore and offshore. For example, a subterranean well can be constructed using a pipe string (e.g., casing, liners, expandable tubulars, etc.), which can be run into a wellbore and cemented in place. The process of cementing the pipe string in place is commonly referred to as “primary cementing.” In a typical primary cementing method, a cement composition can be pumped into an annulus between the walls of the wellbore and the exterior surface of the pipe string disposed therein. The cement composition can set in the annular space, thereby forming an annular sheath of hardened, substantially impermeable cement (i.e., a cement sheath). The cement sheath can support and position the pipe string in the wellbore and bond the exterior surface of the pipe string to the subterranean formation. The cement sheath surrounding the pipe string functions to prevent the migration of fluids in the annulus among other things, and to protect the pipe string from corrosion.
A broad variety of well cement compositions have been used in subterranean well cementing operations. Such well cement compositions can be made by mixing portland cement with water and often with one or more other additives such are retarders, accelerators, lightweight additives. The additives can be either dry powder, or liquid or both. The components are mixed under certain mixing conditions (e.g., mixing speeds, mixing times, and other conditions). For example, industry guideline specifications for laboratory experiments designed to mimic field operations, which include quantities and mixing conditions, for mixing a specified volume of a cement slurry are provided, e.g., by institutions such as the American Petroleum Institute (API) or other institutions.
A variety of mixing equipment are employed in the field to mix the broad variety of cement compositions. Examples of such mixing equipment include batch mixers and RCM® IIIr Mixers (a Halliburton Energy Services Inc. mixing system). Certain mixing equipment, e.g., mixing equipment implemented under laboratory conditions, can be used to mix a specified volume of well cement slurry according to the industry guideline specifications (e.g., the API specifications). For example, the laboratory mixing equipment can mix the specified volume under API specifications such as specified time and mixing RPM. In some situations, additives are incorporated into the well cement slurry or larger volumes of slurry are mixed (or both). The energy consumed by the mixing process in those situations may exceed the energy consumed during mixing in other situations. Capabilities are available to modify the mixing equipment to provide the additional energy to mix the well cement slurry with the additives or the larger volumes of well cement slurry (or both). The mixing capabilities of different mixing equipment to mix well cement slurry can differ. For example, the capabilities of field equipment, i.e., equipment used at or near a well site to mix well cement slurry, can differ from the mixing capabilities of other equipment, e.g., the mixing equipment used under laboratory conditions. The difference in capabilities can affect the mixability of the well cement slurry under industry guideline specifications or the quality of the mixed well cement slurry (or both).
Like reference symbols in the various drawings indicate like elements.